The following puncture instrument has been known in the past as this type of puncture instrument.
This puncture instrument has a tubular main case with an opening, a lancet holder provided inside this main case, a biasing member that biases this lancet holder toward a front end opening in the main case, a locking pawl that locks the lancet holder, a first manipulation button, and a second manipulation button. When the first manipulation button is pressed, the locking pawl is released and the lancet holder moves under the biasing of the biasing member toward the front end side of the main case. When the second manipulation button is pressed, the lancet is separated from the lancet holder.
When a user measures a blood glucose level, in the initial mounting operation, a puncture needle cartridge having a lancet is inserted into the opening of puncture instrument, and the lancet is mounted to the lancet holder of the puncture instrument. Then, in the puncture operation, the user executes puncture by pressing the first manipulation button of the puncture instrument. After this, the user presses the second manipulation button of the puncture instrument to release the lancet from the lancet holder, and the puncture cartridge is disengaged from the puncture instrument and discarded.
Thus, a series of puncture-related operations is performed (mounting operation, puncture operation, disposal operation) in the measurement of blood glucose levels (see Patent Literature 1, for example).    Patent Literature 1: Japanese Laid-Open Patent Application 2004-33440